January Transfer Window: Manchester City sign Aymeric Laporte; Arsenal close in on Pierre-Emerick Aubameyang

London: Manchester City completed the signing of Aymeric Laporte on Tuesday but Arsenal's move for Pierre-Emerick Aubameyang hinges on other transfers being agreed as Premier League clubs scramble to beat Wednesday's deadline.

The Premier League leaders are reported to have paid Spanish club Athletic Bilbao £57 million ($80 million, 65 million euros) for the defender, taking him past Kevin De Bruyne (£55 million) as their record signing.

Manchester City have signed Aymeric Laporte from Athletic Bilbao. AFP

The 23-year-old is also the second most expensive defender in history behind Virgil Van Dijk, who cost Liverpool £75 million from Southampton earlier this month.

"I am very happy to be here," Laporte said. "City are a club with a lot of ambition and they are one of the best teams in Europe.

"I am looking forward to working under Pep Guardiola and trying to help the club to achieve success."

City boss Guardiola said Laporte was ready to play straight away but may need time to adapt to the Premier League.

"He's fit, he's been playing the last period," Guardiola told reporters. "Of course he has to adapt because the Premier League is special in many senses.

"He is intelligent, he will read what is the situation. Even for English players, when they come into the Premier League it's always a little bit tough. We will be patient because he doesn't come for three months, he comes for five years."

Guardiola has now spent more than £200 million simply on reinforcing his defence alongside the acquisitions of Benjamin Mendy (£52m), John Stones (£47.5m) and Kyle Walker (£45m).

A France international at all youth levels, Laporte has been frustrated at continually being overlooked by senior team coach Didier Deschamps

Aubameyang

Borussia Dortmund striker Aubameyang is poised to make a £60 million switch to Arsenal, who are looking to bolster their forward options after the departure to Manchester United of Alexis Sanchez.

The BBC said Arsenal had agreed a fee with the Bundesliga club and personal terms with Gabon international Aubameyang, 28, but the German club will only sanction the move if they get a replacement.

Arsenal striker Olivier Giroud is reportedly a key cog in the transfer — either as a direct replacement for Aubameyang or as part of a three-way deal, with Giroud moving to Chelsea and Michy Batshuayi swapping Stamford Bridge for Dortmund.

Reports in Italy suggest a Chelsea bid for Roma's former Manchester City striker Edin Dzeko has been unsuccessful.

Elsewhere, Liverpool striker Daniel Sturridge, 28, left Anfield on a loan deal until the end of the season after slipping down the pecking order under Jurgen Klopp.

Barcelona winger Gerard Deulofeu has become Javi Gracia's first signing as Watford manager after arriving at Vicarage Road on loan until the end of the season.

Millwall re-signed veteran Australia international Tim Cahill, 14 years after he left the Den to join Everton.

"It's hard to put into words (what it feels like to wear a Millwall shirt again) — I'm still taking it in now," the 38-year-old told Millwall's website.

Celtic have signed Chelsea midfielder Charly Musonda on an 18-month contract, with left-back Baba Rahman departing Stamford Bridge for Schalke in a similar arrangement.